100 On the Biast Furnace in the Manufacture of Iron. 
the world, and entering our ports free of duty ; at the same time 
it will increase the value of those works whose wood-land has 
been diminished by a too rapid and improvident use of fuel. 
I next pass on to make a few remarks about the refining fur- 
nace used in the working of iron. In these furnaces the air is 
thrown by one or two tuyers, into a crucible filled with charcoal, 
into which the pig to be refined, along with scraps coming from . 
previous operations, is placed in a certain relative position. The 
changes that take place by the reaction of the air upon the coal, 
is similar to what occurs in the lower part of the blast furnace, 
namely, the conversion of the oxygen into carbonic acid, which 
is immediately changed into carbonic oxide. The analyses of 
the gases taken from the centre of the furnace, prove that the 
transformation of the oxygen into carbonic acid corresponds to 
the position where the workmen constantly place the iron that is 
about to be forged, and this is just what we should — as it 1s 
the point of maximum temperature. 
Ebelman states that the atmosphere which sommes the sapls: 
ed iron, contains hardly a trace of carbonic acid, either in the 
blast or puddling furnace; this being contrary to the opinion 
which is generally admitted, that the decarbonization of the iron 
takes place by the action of the air during the melting of the pig, 
but it would appear that this reaction is attributable to the protox- 
ide of iron covering the surface of the-mass undergoing refining. 
In the second period of refining, in the puddling properly speak- 
ing, it is easy to deduce from the analyses of the gas, that there. 
is oxidation of a considerable portion of the iron by the ee 
of the air thrown in at the tuyer. 
‘Here again much of the fuel ‘passes off under the form of car- 
bonic oxide, thereby causing considerable waste. . Of late yearsa 
modification has been introduced into the refining furnaces, even 
when the waste gases from the blast furnace are not employed; 
a modification by which none of the combustible is lost. A few 
words will suffice to explain how this is accomplished. x 
All the furnaces are modifications of 
the reverberatory furnace. The fuel is ;o 
: 
| 
~ 
. Fig. 2. 
the zeit, by a bellows am otherige. 
